U.S. patent number 4,302,910 [Application Number 06/125,391] was granted by the patent office on 1981-12-01 for pneumatically operated grinding apparatus.
This patent grant is currently assigned to Festo-Maschinenfabrik Gottlieb Stoll. Invention is credited to Hans-Dieter Tschacher.
United States Patent |
4,302,910 |
Tschacher |
December 1, 1981 |
Pneumatically operated grinding apparatus
Abstract
A pneumatically operated grinding apparatus having a dust
removal structure. The grinding apparatus has a housing and a
movable work plate which is driven by a compressed-air motor. An
inlet piping connection is provided for compressed air and is
connected in fluid circuit with an inlet opening of the
compressed-air motor. A suction piping connection is also provided
which is connected to the inside of the housing and to which a
suction device can be connected. A discharge-air piping connection
is provided which is connected to an outlet of the compressed-air
motor and is guided outwardly from the housing.
Inventors: |
Tschacher; Hans-Dieter
(Reichenbach, DE) |
Assignee: |
Festo-Maschinenfabrik Gottlieb
Stoll (Esslingen, DE)
|
Family
ID: |
6064169 |
Appl.
No.: |
06/125,391 |
Filed: |
February 27, 1980 |
Foreign Application Priority Data
Current U.S.
Class: |
451/295; 451/357;
451/456 |
Current CPC
Class: |
B24B
55/105 (20130101) |
Current International
Class: |
B24B
55/00 (20060101); B24B 55/10 (20060101); B24B
023/00 (); B24B 055/06 () |
Field of
Search: |
;51/17MT,17R,273,134.5F,17PT,17T ;125/13R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Parker; Roscoe V.
Attorney, Agent or Firm: Blanchard, Flynn, Thiel et al.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. In a pneumatically operated grinding apparatus having dust
removal means, comprising an apparatus housing, in which a work
plate which is driven by a compressed-air motor is movably
supported, an inlet piping connection for compressed air connected
in fluid circuit with an inlet opening of said compressed-air
motor, a suction piping connection which is connected to the inside
of the apparatus housing and to which a suction device can be
connected, and a discharge-air piping connection which is connected
to an outlet of said compressed-air motor, each of said inlet
opening, said discharge-air piping and said suction piping means
including passageway means to the exterior of said apparatus
housing, the improvement comprising wherein said discharge-air
piping connection surrounds said inlet piping connection, wherein
said suction piping connection surrounds said inlet piping
connection and said discharge piping connection, wherein separate
flexible hoses are sealingly connected to said inlet piping
connection, said discharge-air piping connection and said suction
piping connection, wherein an adapter is provided, to which each of
said flexible hoses, which come in the same direction from said
inlet piping connection, said discharge-air piping connection and
said suction piping connection, are sealingly connected, said
adapter having separate axially arranged hose connecting tubes, one
sealingly connected to said hose extending to said inlet piping
connection, another sealingly connected to said hose extending to
said discharge-air piping connection and still another sealingly
connected to said hose extending to said suction piping connection,
said adapter further having outlet openings aligned in different
direction for connection to a compressed-air source, a
discharge-air port and a suction device.
2. The grinding apparatus according to claim 1, wherein at least
said inlet piping connection and said discharge-air piping
connection are arranged coaxially to one another on said grinding
apparatus.
3. The grinding apparatus according to claim 1, wherein a sound
absorber is connected to one of said outlet openings in said
adapter communicating with said discharge-air connection.
4. The grinding apparatus according to claim 1, wherein an oil
separator is connected to one of said outlet openings in said
adapter communicating with said discharge-air connection.
5. The grinding apparatus according to one of the claims 3 or 4,
wherein said outlet opening communicating with said suction piping
connection on said adapter is connected directly to said suction
device.
6. The grinding apparatus according to claim 1, wherein an outlet
opening of said adapter is constructed as a connecting tube which
is constructed coaxially with respect to said hose connecting tubes
for the exhaust dust-containing air.
7. The grinding apparatus according to claim 6, wherein the axis of
the outlet opening for said compressed-air source and the axis of
said outlet opening for said discharge-air port define an angle
with the common axis of said hose connecting tubes.
8. The grinding apparatus according to claim 6 or 7, wherein said
hose connecting tube which carries the flexible suction hose and
said outlet opening for said suction device have the same outside
diameter.
9. The grinding apparatus according to claim 1, wherein said
adapter is a plastic part which is molded in one piece.
10. The grinding apparatus according to claim 1, wherein said hose
connecting tubes on said adapter are coaxial.
Description
FIELD OF THE INVENTION
The invention relates to a pneumatically operated grinding
apparatus.
BACKGROUND OF THE INVENTION
In such known grinding apparatus the outlet opening of the
compressed-air motor communicates with the suction piping
connection through a hose to the suction device for sucking off the
grinding dust.
This has the disadvantage that the grinding apparatus must be
designed for high performance, since it must not only absorb the
amount of air which is needed for the suction of the grinding dust
but also for the discharge air of the compressed-air motor. It is
disadvantageous in this solution, since the oil which is contained
in the discharge air cakes the grinding dust together to form to a
connected mass in the suction device and is very poor in permitting
air to pass therethrough.
The present invention is to provide a further development of a
grinding apparatus so that it can be used together with a suction
device having a low output.
In the inventive grinding apparatus, the discharge air is collected
and discharged separately, and the suction device needs to be
designed only for the air flow which is necessary for sucking off
of the grinding dust. The grinding dust also does not come into
contact with the oil traces and thus does not cake together in the
filter of the suction device. Thus this filter also does not need
to be cleaned as often; a cleaning of the filter which becomes
necessary is simpler, since the filter cake can easily be removed
from it.
With a further development of the invention, a compact arrangement
of the hoses which carry the compressed air and discharge air is
obtained. Furthermore one obtains in a very simple manner the
requirement of providing differently sized cross-sectional
dimensions for the hoses, as it must be chosen in view of the
volume increase of the flow medium created during the exhaust of
the compressed air in the compressed air motor.
With a still further development of the invention, it is achieved
on the one side, that the entire hose arrangement can be handled
externally as one unit. It is thereby particularly advantageous
that the suction hose, which conducts the sucked-off air or the
air-dust mixture, be designed mechanically strong because of the
underpressure existing in it and thus also can hold together the
hoses which lie particularly well in it. Furthermore in this manner
one obtains also the desired large cross section for the suction
piping connection and the suction hose, as it is desired in view of
an unreduced forwarding of the suction output of the suction device
to the grinding apparatus.
A still further development of the invention is preferable in view
of the simple handling of the grinding apparatus. In the known
grinding apparatus, several hoses for the air supply and air
exhaust of the grinding apparatus started out from the apparatus
itself, which hoses were able to get caught on the edges and
corners of the workpiece. A "hose salad" is now avoided with the
invention.
With a still further development of the invention, a splitting up
of the common hose arrangement into individual hoses which extend
in different directions is obtained in a very simple manner.
In a grinding apparatus embodying the invention, a minimum number
of hoses exist also behind the adapter. The discharge air of the
motor is exhausted through the deadener at the adapter to the
atmosphere, which does not interfere since the adapter can be a
considerable distance away from the actual working place.
Of course, it is possible to also choose a different form for the
adapter, thus for example it may be round or cylindrical, if other
situations permit this to be necessary.
The further development of the invention permits the use of the
same hose material for the suction hose between the grinding
apparatus and the adapter and between the adapter and the suction
device.
The further development of the invention is advantageous in view of
the secure placement of the adapter on a base and in view of the
moving and removing of various hoses by rotation.
In a grinding apparatus embodying the invention, only two hoses
need to exist for the air supply and the air exhaust for the
grinding apparatus. The direct mounting of the deadener in the
discharge-air piping connection is particularly not disadvantageous
for grinding apparatus having a low work performance, since the
discharge air exits from the deadener practically completely
relaxed and diffused.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be discussed in greater detail hereinafter with
reference to one exemplary embodiment and with reference to the
enclosed drawings, in which:
FIG. 1 is a longitudinal cross-sectional view of a pneumatically
operated grinding apparatus embodying the invention; and
FIG. 2 is an axial cross-sectional view of an adapter, through
which a single hose which is connected to a suction device, an
individual hose which is connected to a compressed-air source and a
deadener which is connected to the outside atmosphere and is at the
same time oil-separating, can be connected to a coaxial arrangement
which extends to the grinding apparatus illustrated in FIG. 1.
DETAILED DESCRIPTION
FIG. 1 illustrates a pneumatically operated grinding apparatus
having a two-part work plate 10 composed of parts 10A and 10B, to
which part 10A an abrasive paper (not shown) can be clamped. The
work plate 10 has on its upper side two upright walls 12, 14 which
serve as a guide for an outer race of an eccentric roller formed by
a roller bearing 16. The roller bearing 16 is mounted with its
inner race fixedly engaging an eccentric end section 18 of a drive
shaft 20. The drive shaft 20 is supported through a further roller
bearing 22 in the bottom wall 24 of a motor housing 26. The latter
is represented schematically in the drawing as a one-piece housing
and consists as a rule of a plurality of closely connected housing
segments. Further details concerning the design of the apparatus
and the drive will be understood by skilled persons and, therefore,
further discussion thereof is believed unnecessary.
The drive shaft 20 has secured thereto in a work chamber 28 of the
motor housing 26 a hub member 30 having radially outwardly opening
grooves 32. The axis of the hub 30 is laterally offset with respect
to the axis of the drive shaft 20. Sealing blades 34 are arranged
radially movably in the grooves 32 so that they will be thrown
radially outwardly by the centrifugal force, for example, during
rotation of the shaft 20. The drive shaft 20, the hub member 30 and
the sealing blades 34 form together the rotor of a rotation piston
machine.
An inlet opening 40 for compressed air is constructed in a section
of the peripheral wall 38 of the motor housing 26 and which defines
the work chamber 28, which section is located closest to the axis
of the drive shaft 20. An outlet slot 42 for the exhaust air is
elongated in the peripheral direction starting at the section of
the peripheral wall 38 farthest removed from the axis of the drive
shaft 20 and terminating adjacent the inlet opening 40, so that
during the returning of a sealing blade to the inlet opening, a
compression of air does not occur.
The inlet opening 40 is connected through a rotary slide valve 44
to an inlet piping connection 46. The outlet slot 42 is connected
to a discharge-air collecting chamber 48 defined on the inside
thereof by the outside wall of the motor housing 26 and on the
outside thereof by an apparatus housing 50. The chamber 48 is
connected to and communicates with a discharge-air piping
connection 52 which is formed by the housing structure 50 and which
coaxially surrounds the inlet piping connection 46.
The work plate 10 has openings 56 therein which communicate with an
annular chamber 58 formed between the two parts 10A and 10B. The
chamber 58 is, in turn, connected to and communicates with a
suction channel 70, which can be constructed bellowslike.
A bottom flange 64 and edge walls 66, 68 are appropriately formed
and connected to the walls 12 and 14, which together form a
cup-shaped protective housing 67 surrounding the roller bearings 16
and 22 and the end section of the drive shaft 20. In this manner,
the grinding dust is prevented from penetrating into the roller
bearing 16 and 22.
The eccentric portion 18 of the drive shaft 20 is balanced at two
points, for example by balancing weights 74,76 fastened to the
drive shaft 20.
A pressure hose 78 is moved onto and is connected to the inlet
piping connection 46. A discharge-air hose 80 is moved onto and
connected to the discharge-air piping connection 52. A suction-air
hose 82 is moved onto and is connected to the suction piping
connection 62. The pressure hose 78 is a common flexible hose which
is designed for the operating pressure of the grinding apparatus.
The discharge-air hose 80 is a relatively thin flexible hose, which
is completely sufficient (and is advantageous in view of the
movability of the entire coaxial hose arrangement), since the
discharge air in the hose 80 is under a higher pressure than the
sucked-off air in the hose 82, so that also the wall of the
discharge-air hose 80 is subject to tension in the peripheral
direction. The suction hose 82 must be sufficiently strong that it
does not collapse under the underpressure which exists in it; on
the other hand this hose too is not to influence too much the
flexibility of the entire coaxial hose arrangement. Therefore, a
bellowslike hose is used. All these hoses can be obtained as
plastic hoses in the marketplace.
One recognizes that only one single hose appears from the outside
to be connected to the grinding apparatus and must be moved
together with the grinding apparatus. With this arrangement, the
convenience in handling of the grinding apparatus is substantially
improved and the danger of snagging the hose on edges and corners
of the workpiece is substantially reduced.
FIG. 2 illustrates an adapter which as a whole is identified by the
reference numeral 84 and through which a transition is created
between the individual supply hoses for supplying and evacuating of
the grinding apparatus and the coaxial hose arrangement.
The adapter 84, which is a single or multipart plastic molded part,
has in the illustrated exemplary embodiment a substantially
square-shaped main body 86. The shape of the main body may,
however, also be different, for example it may be cylindrical or
round. On the side adjacent the grinding apparatus, coaxially
arranged tubes of increasing diameter are formed onto the main
member 86: a first connecting tube 88, the outside diameter of
which corresponds with the outside diameter of the inlet piping
connection 46 and onto which the second end of the pressure hose 78
is fixedly fastened; a second connecting tube 90, the outside
diameter of which corresponds with the outside diameter of the
discharge-air piping connection 52 and onto which the second end of
the discharge-air hose 80 is fixedly fastened; and a third
connecting tube 92, the outside diameter of which corresponds with
the outside diameter of the suction piping connection 62 and onto
which the second end of the suction hose 82 is fixedly
fastened.
The main body 86 of the coaxial connecting tube arrangement has on
the opposite side remote from the grinding apparatus a coaxial
connecting tube 94. The outside diameter of the tube 94 equals the
outside diameter of the suction piping connection 62 and the third
connecting tube 92--the aforementioned diameters, however, do not
need to be absolutely the same--and which can be connected through
a not illustrated, fixedly fastened hose of the same material as
the suction hose 82 to a not shown suction device. The connection
to the not illustrated suction device may, however, also occur
directly, without a hose. The connecting tube 94 communicates with
the third connecting tube 92 through a graduated ring chamber 96
radially offset from the central axis, the radially outer limit of
which is a continuation of the inner wall of the third connecting
tube 92 and the connecting tube 94 and the radially inner limit of
which is defined by a partial cylindrical support block 98, which
carries the first connecting tube 88 and the second connecting tube
90.
A first longitudinal channel 100 is constructed in the support
block 98, which channel is an extension of the inside of the first
connecting piece and is connected through a radial channel section
102 to a connecting opening 104, into which a connecting pipe (not
illustrated) can be screwed for facilitating a supply or compressed
air.
A second longitudinal channel 106 is provided in the support block
98 and is an extension of the inside of the second connecting tube
90 and is connected through a radial channel section 108 to a
second connecting opening 110, into which a sound absorber or an
oil separator (not illustrated) can be secured therein, which is
directly connected to the atmosphere. In place of it, it is also
possible to screw in a connecting pipe to facilitate an air
discharge through a discharge-air hose.
The aforementioned connections, however, can also be created in a
different manner than by screwing, for example as snap or plug-in
connection. The adapter 84 is during operation provided a greater
distance away from the grinding apparatus, so that it remains
stationary during the movement of the grinding apparatus. Also in
the case of grinding apparatus having a high output, the exhaust
air which is emitted from the sound absorber or the oil separator
is so far away from the actual working place that no grinding dust
whatsoever is raised or blown around. The block-shaped design of
the main body 86 facilitates a secure placement of the adapter on a
plane base or a slight temporary clamping; one can so easily hold
or clamp the adapter, when the various hoses are rotatingly
telescoped under a press fit onto the various connecting tubes of
the adapter or are removed therefrom.
It is possible in different, not illustrated embodiments to make
the adapter connectible directly to connecting tubes on the suction
device.
In a different variation, the arrangement can be such that the
adapter is integrated in a suction system having an integrated
supply port and an evacuation port, so as to facilitate a compact
building foundation.
Although a particular preferred embodiment of the invention has
been disclosed in detail for illustrative purposes, it will be
recognized that variations or modifications of the disclosed
apparatus, including the rearrangement of parts, lie within the
scope of the present invention.
* * * * *